Shave, stay out of the sun, come in clean. The prep is simple — and it’s most of what separates a great session from a rescheduled one.
If you remember one thing from this page, make it this: shave the treatment area 12 to 24 hours before your appointment, and do not wax, pluck, thread, or epilate for about four weeks beforehand. Those two sentences carry most of the weight. Everything else on this page is a refinement.
The reason comes down to what the laser is actually aiming at. The Candela GentleMax Pro works by sending light energy into the pigment in your hair. That pigment absorbs the energy, converts it to heat, and carries that heat down the hair shaft to the follicle at the root. The follicle is the target. The hair is only the delivery wire. Waxing, tweezing, threading, and epilating all remove the hair from the root — which means the wire has been pulled out and there is nothing left to conduct energy to the target. The follicle is still there. The laser just can’t reach it. That is why we ask for roughly four weeks of no pulling: it gives every follicle in the area time to grow its hair back and re-enter the active phase where treatment actually does something.
Shaving, by contrast, is exactly what we want. It cuts the hair off at the surface while leaving the root and the shaft below the skin fully intact. A clean shave also means the laser’s energy goes down into the follicle instead of burning off surface hair — which is more comfortable for you and more productive for the session. After twenty years and more than 100,000 treatments, the single most common reason we have to reschedule someone is prep, not skin type. It is worth ten minutes of your attention.
We are going to spend more time on this than most practices do, because in St. Louis it is genuinely the thing that derails the most appointments. Missouri summers are long, humid, and spent outdoors. Between June and September people are at the ballpark, on the Katy Trail, floating the Meramec, on a boat at the Lake of the Ozarks, or sitting through a two-hour soccer game in Kirkwood. Nobody thinks of any of that as “tanning.” Your skin does.
Here is why it matters. The laser distinguishes between the pigment in your hair and the pigment in your skin, and it delivers energy to the darker of the two. When your skin has recently tanned, its melanin level rises, that contrast narrows, and more of the laser’s energy gets absorbed by the skin instead of by the follicle. That raises the risk of a pigment change — a lighter or darker patch where we treated — and it also means we may need to dial settings down to stay safe, which makes the session less effective. Neither outcome is what you paid for.
So: no deliberate sun exposure on the treatment area for about two weeks before your appointment, no tanning beds, and no self-tanner or bronzing lotion for at least two weeks — self-tanner counts even though it is only staining the surface, because the laser reads that stain as pigment and reacts to it. If you have a sunless tan on the area, it needs to be fully exfoliated off before we treat, and “mostly gone” is not the same as gone. This is also why a lot of our St. Louis clients start their series in October or November: you finish four or five sessions through a Midwest winter, when your skin is at its natural baseline and you’re covered up anyway, and you walk into the next summer already several sessions in.
If you can’t avoid being outside — and in a Missouri July, you can’t — use a broad-spectrum SPF 30 or higher on the area, reapply it honestly, and cover up where you can. Sunscreen is not a loophole, but it is a real difference. Just tell your provider the truth about your sun exposure at check-in. We would far rather move your appointment two weeks than treat skin that isn’t ready.
Stop waxing, plucking, threading, epilating, and any hair removal cream that dissolves hair below the surface. Shaving and trimming are fine from here on. If you have any electrolysis history on the area, mention it at your consult.
No intentional sun on the area, no tanning beds, no self-tanner or bronzer. SPF 30+ daily if the area is exposed. Also a good moment to pause retinoids on the treatment area and flag any medication changes to us.
Shave the full area with a fresh blade. Not the morning of, if you can help it — a day of settling lets any razor irritation calm down. Then leave the skin alone: no scrubs, no new products.
Shower and wash the area with plain soap. Come in bare: no lotion, no oil, no deodorant if we’re treating underarms, no makeup or SPF residue if we’re treating your face. Wear something loose that gets to the area easily — and something you don’t mind changing out of.
Deodorant, antiperspirant, body lotion, self-tanner, makeup, and heavy fragrance on the treatment area. Anything sitting on the skin can absorb energy or interfere with the handpiece’s contact and cooling. If you forget, tell us — we’ll clean it off, it just costs a few minutes.
Caffeine won’t hurt you here, but if a large coffee already makes you jittery, it can make you read every pulse as sharper than it is. Some clients prefer to skip the second cup on treatment day. Others don’t notice at all. You know your own body.
On comfort generally: the GentleMax Pro has integrated cooling that fires a burst of cryogen with each pulse, and most clients describe the sensation as a quick snap rather than anything they’d call painful. Small areas like an upper lip or underarms are over in a few minutes. If you want the full walkthrough of what actually happens once you’re in the room, read the treatment process. What happens afterward — the redness, the shedding, the sun rules that continue for a couple of weeks — is covered in aftercare.
This is the part people skip because it feels like paperwork, and it is the part that most affects whether we can treat you safely today. Some medications make your skin photosensitive — meaning it reacts more strongly to light than it normally would. Common ones include tetracycline antibiotics like doxycycline and minocycline (often prescribed for acne or after a tick bite, which in this part of Missouri is not a rare thing), topical and oral retinoids, certain diuretics, some antihistamines, and even St. John’s Wort, which people rarely mention because it’s sold on a shelf at the grocery store rather than filled at a pharmacy. Herbal supplements count. Tell us anyway.
Isotretinoin — Accutane — deserves its own line. Your provider will want to know if you have taken it recently, and standard practice is to wait a stretch of months after your last dose before laser treatment. Do not guess at the timeline on your own; bring us the date and we’ll work from there. The same goes for a recent chemical peel, microdermabrasion, or any resurfacing on the area, and for a history of cold sores if we’re treating around the mouth — that last one is worth flagging early, because there are simple steps that can be taken beforehand.
Hormones matter too, and honestly more than most people expect. Conditions like PCOS, thyroid disorders, and hormonal shifts around pregnancy or perimenopause can keep stimulating new follicles into growing, which is why results vary from person to person and why some clients benefit from occasional maintenance sessions after their initial series. That is not a failure of the treatment — it is your body doing what hormones do — but you deserve to know it going in rather than being surprised at session seven. And if you are pregnant or nursing, tell us. Laser hair removal has not been studied in pregnancy, so we don’t treat during it. We’ll be glad to see you afterward.
None of this is a quiz you can fail. It is a conversation, and it happens at your consultation, where we look at your hair color, your skin tone, and your history together and tell you honestly what to expect. If you’re still deciding whether this is right for you at all, start with am I a candidate. If you already know you’re in, book the consult and we’ll build the plan around your real life — Missouri summers included. Call us at (636) 391-0015 with anything this page didn’t answer.